This application is directed to an approach for improved energy efficiency in combustion heated convection ovens.
Commercial combustion convection ovens utilize combustion of a gas to supply the heat to the cooking cavity to heat the food therein. As such, these ovens are sometimes referred to as “gas-fired” convection ovens. Such ovens also employ fans to forcibly circulate the air in the cooking cavity so as to improve thermal transfer to the food. Some designs of commercial combustion convection ovens are shown in U.S. Pat. No. 5,655,511 to Prabhu, and/or sold under the TRUVECTION and MARATHONER GOLD names by the Southbend division of Middleby Marshall, Inc. of Elgin, Ill.
While such ovens have been commercially successful, such designs may not be entirely energy efficient. For example, such ovens allow for the flow of air through the oven, from the air intake upstream of the burners, through the combustion chamber and cooking cavity, and out the exhaust, both while the burners are on and while the burners are off. The flow through the oven is advantageous while the burners are on, so that sufficient fresh air is supplied to the burners so that they may safely operate. However, while the burners are off, airflow through the oven, and particularly the cooking cavity, has the undesirable effect of removing heat unnecessarily from the cooking cavity, in the form of the heated exhaust air. In addition, such ovens may have multi-speed fans, but be designed to ensure sufficient airflow under worst case conditions, which may result in unnecessarily large amounts of airflow through the oven under better conditions. Once again, this may result in unnecessarily large amounts of heat being extracted from the cooking cavity, with a resulting loss in efficiency. As such, there remains a need for alternative approaches to combustion cooking ovens.